edu.upc.dama.dex.algorithms
Class StrongConnectivityGabow

java.lang.Object
  edu.upc.dama.dex.tasks.Task
      edu.upc.dama.dex.tasks.CompositeTask
          edu.upc.dama.dex.algorithms.Connectivity
              edu.upc.dama.dex.algorithms.StrongConnectivity
                  edu.upc.dama.dex.algorithms.StrongConnectivityGabow

All Implemented Interfaces:

Algorithm

public class StrongConnectivityGabow
extends StrongConnectivity

This class can be used to solve the problem of finding strongly connected components in a directed graph.

Concretely, it consists in finding components where every pair (u,v) of nodes contained in it has a path from u to v using the specified direction for each edge type. This implementation is based on the Gabow algorithm.

It is possible to set some restrictions after constructing a new instance of this class and before running it in order to limit the results. Those restrictions are:

• The set of edge types which will be navigated through while traversing the graph. The method is Connectivity.addEdge(int edgetype) for adding one edge type and Connectivity.addAllEdges() for adding all edge types.
• The set of node types which will be navigated through while traversing the graph. The method is Connectivity.addNode(int nodetype) for adding one node type and Connectivity.addAllNodes() for adding all node types.

For each instance of this class, it is only allowed to run the algorithm once.

After the execution, we can retrieve the results stored in an instance of the class ConnectedComponents using the Connectivity.getConnectedComponents() method. Please, see edu.upc.dama.dex.algorithms for further information related to how to use this class.

NOTE: It is required to indicate the set of edge types and node types before running this algorithm.

Author:

Sparsity Technologies

Field Summary

Fields inherited from interface edu.upc.dama.dex.algorithms.Algorithm

NAVIGATION_BACKWARD, NAVIGATION_FORWARD, NAVIGATION_UNDIRECTED

Constructor Summary

StrongConnectivityGabow(Graph graph)
Creates a new instance of StrongConnectivityGabow.

Method Summary

void	close() Closes the instance.
void	run() Runs the algorithm in order to find the connected components.

Methods inherited from class edu.upc.dama.dex.algorithms.Connectivity

addAllEdges, addAllNodes, addEdge, addNode, getConnectedComponents, setMaterializedAttribute

Methods inherited from class edu.upc.dama.dex.tasks.CompositeTask

cancel, execute, init

Methods inherited from class edu.upc.dama.dex.tasks.Task

main

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StrongConnectivityGabow

public StrongConnectivityGabow(Graph graph)

Creates a new instance of StrongConnectivityGabow. After creating this instance is required to indicate the set of edge types and the set of node types which will be navigated through while traversing the graph in order to find the strong connected components.

Parameters:

graph - Graph on which the algorithm will be run.

Method Detail

close

public void close()

Description copied from class: Connectivity

Closes the instance.

Once executed, the instance becomes invalid.

Specified by:

close in class Connectivity

run

public void run()

Description copied from class: Connectivity

Runs the algorithm in order to find the connected components.

This method can be called only once.

Specified by:

run in class Connectivity